With the spread of an ink jet recording system, there is a demand for speeding up of recording and improvement in the quality of recorded images, such as images of characters and photographs, when recording is conducted on plain paper by ink jet recording.
For example, there is a demand for recording official documents, photographic images of digital cameras, and various kinds of information put on internet websites on plain paper at high speed and on both sides of the plain paper. There is also a demand for achieving such clear image quality as in recorded images obtained with a laser beam printer. There is further a demand for obtaining a high image density when character images are printed and providing sharp character images that are inhibited from being defaced even when the character images are small.
In recorded images such as color photographs and tables, there is also a demand for inhibiting bleeding at a color boundary portion, which is caused upon contact of a plurality of recording inks of different colors with each other.
In order to meet such demands, there has been proposed an ink, which contains organic ultrafine particles having an average particle size of 0.5 μm or less and having been internally and three-dimensionally crosslinked and provides high-density images inhibited from bleeding on plain paper (see Japanese Patent Application Laid-Open No. 2004-195706). There has also been proposed an ink that contains a permeability-imparting agent wherein the content of the permeability-imparting agent is made larger than the content in which the surface tension of the ink composition, which decreases according to the increase in the amount of the agent, ceases to decrease (see Japanese Patent Application Laid-Open No. 2003-301129).